The increasing prevalence of human autoimmune diseases and immune disorder-related diseases, e.g. cardiovascular disease, diabetes, and neuronal degenerative diseases, presents a challenge to find more effective therapies. Stem cell-based therapy, including embryonic and adult stem cells, provides a rational treatment tool for regenerative medicine and has potential to revolutionize modern therapeutics. Because of their high potential for self renewal and pluripotent differentiation capability, embryonic stem (ES) cells have become a very active area of investigation. Ethical concerns, however, have limited their availability and practical usefulness. Leaving aside these ethical concerns, using in vitro fertilization (IVF) and altered nuclear transfer (ANT) to generate ES cells is made problematic by the complexity of required technologies.
Recently, human umbilical cord blood has been used as a source of stem cells to repopulate the hematopoietic system and other organs. Cord blood provides an abundant source for generation of stem cells, including mesenchymal stem cells and monocyte-derived stem cells. Stem cells expressing ES molecular markers have been reported from cord blood after removal of hematopoietic cells (including deletion of all leukocyte common antigen CD45 positive cells). However, the scarcity of this previously-described cell population [in cord blood significantly restricts its practical application.
Several other embryonic-like stem cells derived from adult sources rather than embryonic sources have also been disclosed. For example, U.S. Pat. No. 7,045,148, United States Patent Applications Serial Numbers 2005/0148034, 2005/0118715, 2004/0028660, 2003/0235909, 2002/0160510, 2003/0180269 and International Patent Application Number WO 03/068937 disclose embryonic-like stem cells extracted from the placenta or from the umbilical cord blood. United States Patent Application Serial Number 2006/0078993 discloses embryonic-like stem cells derived from the amniotic membrane of umbilical cord. The stem cells disclosed in these patents or patent applications are of mesenchymal origin which do not express the CD45 marker (CD45−). In another example, United States Patent Application Serial Number 2006/0147426 discloses stem cells derived from human bone marrow. International Application PCT/US06/38524 by Zhao and Mazzone discloses an embryonic-like stem cell isolated from the umbilical cord blood that is suitable for stem cell therapies. Additionally, International Application PCT/US07/22260 by Zhao and Mazzone discloses an embryonic-like stem cell isolated from the peripheral blood that is also suitable for stem cell therapies.